Japan's consumer prices fell 0.5 percent in June from a year earlier for the fourth straight month of decline, the government said Friday, adding pressure on the Bank of Japan to further ease monetary policy to boost inflation.

The core consumer price index, which excludes volatile fresh food prices, stood at 103.0 against the base of 100, the Ministry of Internal Affairs and Communications said.

The 0.5 percent decline, the biggest drop since March 2013, shows Japan has yet to overcome deflation despite efforts by Prime Minister Shinzo Abe and the central bank's large-scale monetary easing policy.

Falling crude oil prices continued to weigh on consumer prices, as energy prices plunged 11.8 percent from a year earlier, with gasoline prices sliding 13.9 percent and electricity fees dropping 9.5 percent.

The core CPI for Tokyo's 23 wards in July, seen as indicating nationwide price moves down the road, dropped 0.4 percent from a year earlier to 101.4 for the seventh straight month of decline.

Separate data showed average monthly household spending in June decreased an inflation-adjusted 2.2 percent from a year earlier to ¥261,452 ($2,496) for the fourth consecutive month of decline, the ministry said.

Household spending figures are a key indicator of private consumption, which accounts for about 60 percent of Japanese gross domestic product.